1. Field of the Invention
The present invention relates to a magnetic field indicator which detects the possibility of damage to data stored on magnetic recording media, and, more particularly, to a visual magnetic field indicator which can be constructed in a variety of forms and embodiments in order to provide close proximity and conformity to the recording media being protected.
2. Description of the Related Art
Magnetic recording media is ubiquitous in our present society. Examples of such media include computer disks and tapes, audio and video cassette tapes, and magnetic strips utilized on a wide variety of cards and other objects, such as credit cards, security pass cards, and the like. Obviously, the data stored on this wide variety of media is extremely valuable. The loss of some or all of this data could lead to a severe loss of time and money, in addition to a great deal of personal frustration.
Data stored on magnetic recording media may be destroyed, in whole or in part, or corrupted, when impinged upon by an external magnetic field. For example, during transportation or in regular use, valuable information contained on magnetic recording medium may be lost due to magnetic fields generated from a variety of sources. Such sources include music speakers, refrigerator magnets, or other magnetized objects.
Software vendors, computer users, automatic teller machine and credit card companies and users, recording artists, and others have a substantial investment in their recorded information. However, heretofore there has not been an adequate mechanism for economically protecting such data for a wide variety of users.
Devices have been developed which are capable of sensing the presence of harmful magnetic fields that can damage data on recording media; however, they have been found to suffer from a number of shortcomings. For example, one type of device comprises a magnetic field alarm indicator which includes a complicated arrangement of electronic devices. Another device utilizes an antenna to focus magnetic energy at a point detector. Although it is possible that these systems may be useful in applications dealing with large computer installations, systems of this sort are prohibitively expensive for the average computer user and would typically be useless for protecting data on cassette tapes, credit cards and the like. Other attempts to provide a magnetic field indicator have yielded devices which exhibit unacceptable levels of sensitivity because they could not be positioned with sufficient proximity to the data to be protected.
Presently, the technology is available to produce substances which contain ferrite-encapsulating microspheres. These substances are capable of providing a visual indication of the presence of a magnetic field. For example, U.S. Pat. Nos. 4,783,336 and 4,929,400 disclose methods for producing microspheres. However, heretofore such materials have generally been employed in biological areas, or for the purposes of amusement in such devices as magnetic scratch pads.
Thus, there is a need for a magnetic field damage indicator which is inexpensive and can be positioned with proximity to the data to be protected in order to provide sufficient sensitivity.